package string;

import java.util.Locale;

public class ToUpperCaseDemo {
    public static void main(String[] args) {
        String str="sdf水电费f";
        String up=str.toUpperCase(Locale.ROOT);
        System.out.println(up);
        String lower=up.toLowerCase(Locale.ROOT);
        System.out.println(lower);
    }
}
